How to strengthen the treatment and resource utilization of livestock manure

1. Overview of aquaculture pollution in China

1. Characteristics of manure from livestock and poultry farms. Large quantity, heavy smell,

The annual discharge of livestock manure in China has exceeded 4 billion tons. High nitrogen content, moderate water content and more humus. The water content and C/N depend on whether or not to use liners, the type and quantity of liners, management methods and climate.

2. Impact of farm manure discharge on the environment. Sewage is discharged into rivers at will, and animal carcasses are discarded at will.

3. Outstanding problems-overall layout. Restricted by topography, landform, traffic, habits, experience and even image, the site layout is not reasonable, and each functional division cannot be arranged according to the wind direction and topography. The interaction and influence between facilities in the site are not well considered, and the clean pollution zoning is not clear. Some key parts, or because of inconvenient operation or management, often reduce the epidemic prevention requirements in design, such as isolation rooms, disinfection channels and facilities at entrances and exits, and treatment facilities for sick and dead livestock and poultry.

4. Outstanding problems in environmental protection. Collection and leakage of feces in sports ground; The fecal cleaning process does not match the subsequent fecal treatment process; The choice of fecal treatment process is unreasonable; Poor working environment and high equipment failure rate; Lack of scientific planning, there is no requirement for total livestock and poultry breeding control in different regions; The combination of planting and breeding is not enough, and there is a lack of effective utilization of feces.

Second, the analysis of foreign livestock and poultry farms sewage treatment methods

1. Denmark. There are 22 centralized biogas fermentation stations in China, and each fermentation station is responsible for the manure treatment of livestock and poultry farmers within 5 kilometers. Farmers provide livestock manure to biogas stations free of charge and get a considerable amount of organic fertilizer free of charge. The biogas station is operated by the company, which makes profits through biogas power generation and heating.

2. America. (1) Shallow septic tank system. It is widely used in the southeastern United States, and can be used in all stages of production, every 5? 7 days to clean feces 1 time. Septic tank is 0.6m deep. There is a feces outlet at one side of one end of septic tank in the delivery room. The bottom of septic tank is equipped with a certain slope to discharge feces. After each cleaning, several centimeters of water should be added to the septic tank. (2) Deep cesspit system. Widely used in the midwest of the United States, it can be used in all production stages. The depth of the cesspit is generally 2.5m m, and the dung is sucked away through the hole of the fan when the dung is pumped. The size of septic tanks is generally based on the feces stored for one year.

3. Netherlands. Conveyor dry cleaning technology: the manure and urine are completely separated in the house, and the manure is rich in P and organic matter-compost; Urine: rich in N element-biogas or reverse osmosis treatment.

Third, the technical problems to be solved in sewage treatment of livestock and poultry farms

The links of manure treatment should include: manure collection, manure transportation, manure stacking and storage, manure treatment and utilization.

1. Fecal collection problem-reduction measures. The influence of excrement cleaning mode: the area of excrement pollution in the house, the water consumption for excrement flushing, whether the excrement pollution in the house can be removed in time, the combination of labor intensity and labor intensity, and the treatment and utilization mode of excrement pollution.

2. A hidden pipeline/ditch is used to transport fertilizer in the site. The manure channel in the site should be located below the milking/turning/sewage channel, and its width depends on the flow, below the deep frozen layer.

3. Storage of manure in the site. Using septic tanks and mixing mercury is more conducive to the fermentation of manure.

4. Disposal and utilization of feces. Physical and chemical treatment methods include: solid-liquid separation, flocculation and filtration; Aerobic and anaerobic treatment and biological treatment: composting, biogas, oxidation pond, constructed wetland and membrane treatment.

Solid manure is put into the field as fertilizer, and the treated sewage and biogas slurry can also be sprayed on the farmland as nutrient solution for soilless culture.

Four, livestock and poultry farms sewage treatment technology model

1. Collect feces by dry cleaning or foaming feces. In dry manure cleaning, solid manure is treated by composting or other harmless ways, sewage and part of solid manure are treated by anaerobic fermentation and oxidation pond, and on the basis of nutrient management, organic fertilizer, biogas residue biogas slurry or fertilizer water are applied to field crops, vegetables, fruit trees, tea gardens and trees. Using the method of soaking feces, the feces were treated by anaerobic fermentation and oxidation pond, and then returned to the field for agriculture.

2. Recycling mode. Adopt dry cleaning manure, control production water and reduce water consumption in aquaculture process; Carry out sewage tunnel transportation, rain and sewage diversion and solid-liquid separation on site to reduce the pressure of sewage treatment; The treated sewage is mainly used to wash the manure ditch or pigsty in the field, and the solid manure is treated and utilized by composting, production substrate, cattle padding, fuel and so on. Key elements: matching of process design and engineering technology.

3. Standard discharge mode. Clean with dry manure. After anaerobic and aerobic treatment of farm sewage, the effluent quality meets the requirements of national discharge standards, and solid manure is composted and utilized. Key element: cost.

4. Centralized processing mode. In intensive farming areas, relying on large-scale farms or independent manure treatment enterprises, the manure or sewage from surrounding farms, farming communities and farmers will be collected and treated centrally. It can be solid manure treatment, centralized treatment of aquaculture sewage and centralized treatment of manure.

5. Multi-mode simultaneous (diversified) governance. The combination of various modes can also achieve good results.

Five, the challenge of bad insurance faced by animal husbandry under the new situation

In recent years, a series of laws and policies have been issued intensively: 2065438+200318 October, the the State Council executive meeting passed the Regulations on Prevention and Control of Pollution in Livestock and Poultry Breeding; 2065438+2004 65438+1 October1(the first environmental protection law specifically for aquaculture); 20 13 10 15 The Ministry of Agriculture promulgated the Technical Specification for Harmless Treatment of Dead Animals and began to implement it; On April 24, 20 14, the environmental protection law was revised and passed, and it came into force on April 24, 20 15 1 year 10. The new Law on the Prevention and Control of Air Pollution is being widely consulted and revised, and the air pollution in farms should also be supervised; "Water Pollution Prevention Action Plan (Water Ten Articles)" has been officially promulgated. Before the end of 20 17, the farms and households in the no-breeding area will be closed or relocated.

On April 15, Vice Minister Zhang Taolin said at the press conference of the State Council Office that agriculture has surpassed solid liquid to become the largest non-point source pollution industry in China.

1. This regulation analyzes the main causes of aquaculture pollution. There are several main reasons for the pollution of livestock and poultry breeding industry in China: rapid industrial growth, extensive, low management level and insufficient scale level; Lack of necessary guidance and norms; Unreasonable layout, too concentrated; Disconnected from the planting industry, preferential policies for chemical fertilizers and the reduction of rural labor force have led to a large number of livestock manure not being effectively treated and utilized; There is no perfect animal carcass collection and disposal system.

2. Basic characteristics of laws and regulations. Grasp the big and let go of the small; Whole process management; Strengthen supervision; Prevention first, combining prevention with treatment; Comprehensive utilization is the fundamental way, with utilization as the main and governance as the auxiliary; Give priority to support, encouragement and guidance, supplemented by rewards and punishments.

3. The main content of the regulations is comprehensive utilization and governance. Support comprehensive utilization; Support the combination of planting and breeding, and promote the use nearby; When returning farmland to use, we should consider the land's acceptance capacity and disinfect it to prevent the spread of epidemics; In aquaculture and waste disposal activities, measures should be taken to prevent sewage leakage; Pollutant discharge should reach the total amount, and it shall not be discharged without treatment; Report production and emissions to the environmental protection department; The disposal of corpses should be carried out in strict accordance with national and local regulations to prevent the spread of epidemic situation and environmental pollution. The disposal of corpses enjoys government subsidies; The county-level government should organize to take control measures for the heavily polluted intensive farming areas, including supporting facilities, layout adjustment, relocation and production conversion; Farmers may be compensated by local people's governments at or above the county level according to law for losses caused by planning adjustment, demarcation of prohibited areas and other rectification.

4. The main content of the regulations is incentive measures. Environmental protection and other funds support the construction of pollution control facilities; Policy support for making organic fertilizer from livestock manure: preferential policies such as tax incentives, electricity incentives, priority transportation arrangements, and subsidies for purchasing and using no less than chemical fertilizers; Support power generation for internet access and self-use; Voluntary further emission reduction, according to the agreement signed with the government to apply for incentives, priority to obtain relevant policy support.

5. About the new environmental protection law. Take environmental protection as a basic national policy; Focus on solving the problems and outstanding problems of environmental law; Clarify the government's environmental responsibility (environmental quality, financial investment in environmental improvement, publicity and popularization, emergency treatment, supervision, etc.). ); Environmental obligations of enterprises (cleaner production, discharging quantity, quality and sewage charges according to regulations, installing monitoring equipment, making emergency plans, publishing pollution discharge information, and establishing environmental responsibility system); Environmental protection departments supervise law enforcement (fines for stopping construction, sealing up, suspension of business, administrative detention, investigation of criminal responsibility, etc.). ) and increase penalties for low illegal costs.

6. Thoughts on comprehensive management and utilization of feces. (1) Strengthen the process research and equipment research and development of livestock and poultry manure collection: different scale manure treatment modes and economical and energy-saving treatment technologies (energy-saving, environmental protection and economy). Small farms adopt decentralized collection and unified treatment, while large factories adopt mechanical dung removal, pipeline transportation, centralized storage and efficient treatment and utilization; Research and development of light cylinder intelligent fertilizer collection and fertilization machinery and equipment: bio-safe and effective manure resource technology includes sewage reuse, padding and algae culture; Rain and sewage diversion; Changes in aquaculture technology and production methods. (2) Policy level: highlighting the public welfare of excrement disposal; Take a variety of policy support methods (agricultural machinery purchase subsidies, processing operating expenses subsidies, awards instead of subsidies); Formulate norms for the treatment and application of manure; Considering the layout and scale of aquaculture comprehensively, study and formulate the total livestock and poultry breeding control strategy in different regions of China; Strengthen supervision.